Detergent builders/activators derived from the oxidation and acylation of polysaccharides

ABSTRACT

Detergent builder/activators which can be produced from renewable resources are provided. The detergent builder/activators are obtainable by a process comprising subjecting a poly(saccharide) comprising a vicinal diol moiety to the independent steps of a) oxidative cleavage of a vicinal diol moiety with an oxidizing agent for vicinal diols to introduce carboxylic acid functionality, and b) acylation with an acylating agent.

This invention relates to detergent builder/activators. Morespecifically, this invention relates to detergent builder/activatorsderived by the oxidation and acylation of polysaccharides.

Many detergent compositions, particularly many domestic detergentcompositions, have for many years comprised a significant proportion ofa detergent builder to assist in, amongst other things, the complexationof the ions responsible for water hardness. The detergent builder wascommonly a phosphate, such as sodium tripolyphosphate. However, inrecent times, the presence of phosphates in detergents has come underincreasingly close scrutiny on account of the apparent role ofphosphates in the eutrophication of water courses and consequentialenvironmental damage.

Compounds that have been proposed as alternatives or replacements forphosphates include chelating agents such as EDTA, zeolites, andthreshold agents such as poly(acrylates). Each of these alternatives,however, has its own drawbacks which mitigate against its use. Forexample, concerns have been expressed about the role of chelating agentsin the solubilisation into water courses of potentially toxic heavymetal ions. Poly(acrylates), although of generally low toxicity, sufferfrom a low degree of biodegradibility, leading to some concerns abouttheir accumulation in the environment.

In addition to the concerns about detergent builders, there has alsobeen increasing interest in the use of renewable resources in themanufacture of chemical compounds to, at least in part, reduce relianceon the petrochemical industry. In the field of detergent builders, muchof this interest has focused on the use of starches as raw materials.For example, European patent application no. 0 542 496 discloses thatstarches can be oxidised, predominantly at the C6 position using nitricacid, sulphuric acid and a vanadium catalyst for use as a builder.European patent application no. 0 472 042 discloses that hydrolyticallydemolished starches and dextrins can be oxidised using hypochlorite orperiodate/chlorite to produce detergent builders. Chromium (VI)-basedoxidants have also been proposed for oxidising starches, see for exampleI Feher, Bor-Cipotech, Vol 11, 33, 65 (1961).

In addition to a detergent builder, many detergent compositions alsocomprise a bleaching system comprising a peroxygen oxidant and a bleachactivator. The bleach activator is commonly a compound that reacts withthe oxidant in use, typically at a pH of around 10, to produce anorganic peracid. Many examples of such activators are known in thedetergent field. Commonly the activator comprises one or more acetylgroups as in, for example, the common activatorstetraacetylethylenediamine (TAED) or the acetylated sugar pentaacetylglucose. One disadvantageous feature of conventional activators such asthese is that once the peracid has been generated, the remainder of themolecule provides no additional benefit to the detergent solution.

Russian patent application no. SU 1035030 teaches that acetone-solublecellulose acetates can be produced by first activating the cellulose bytreatment with N₂ O₄ in glacial acetic acid, followed by acetylationwith acetic anhydride. There is no teaching that the product producedhas either builder or activator properties. Russian patent applicationno. SU 1435578 teaches that water-soluble cellulose derivatives can beobtained by first methylolating cellulose, followed by treatment of themethylolated cellulose with N₂ O₄ in dimethylsulphoxide, and thensubsequent acylation with glacial acetic acid. The water-solublecelluloses are taught to be suitable for processing from solution intofibres and films. There is no teaching that the product has eitherbuilder or activator properties.

It is a first object of certain aspects of the present invention toprovide a detergent builder/activator derived from a renewable resourcesuch as a poly(saccharide).

It is a second object of further aspects of the present invention toprovide a process for the production of a detergent builder/activatorfrom a renewable resource such as a poly(saccharide).

It is third object of the present invention to provide detergentcompositions comprising a detergent builder/activator derived from arenewable resource such as a poly(saccharide).

According to one aspect of the present invention, there is provided adetergent builder/activator obtainable by a process comprisingsubjecting a poly(saccharide) comprising a vicinal diol moiety to theindependent steps of:

a) oxidative cleavage of a vicinal diol moiety with an oxidising agentfor vicinal diols to introduce carboxylic acid functionality, and

b) acylation with an acylating agent.

According to a second aspect of the present invention, there is provideda process for the production of a detergent builder/activator comprisingsubjecting a poly(saccharide) comprising a vicinal diol moiety to theindependent steps of:

a) oxidative cleavage of a vicinal diol moiety with an oxidising agentfor vicinal diols to introduce carboxylic acid functionality, and

b) acylation with an acylating agent.

The builder/activators according to the present invention are obtainedfrom poly(saccharides). Poly(saccharides) that can be employed in thepresent invention comprise 2 or more saccharides groups. Many differentpoly(saccharides) can be employed, but preferably the poly(saccharide)is a poly(glycoside). It will be recognised that poly(glycosides)comprise a series of linked glycosidic units. Poly(glycosides) having 2or more linked glycosidic units can be employed as the poly(saccharide)of the present invention. Examples of poly(glycosides) that can beemployed include cellulose and starches, particularly wheat starch, ricestarch, maize starch and corn starch. Other poly(glycosides) that can beemployed include sucrose, amylose and amylopectin, dextrins such ascyclodextrins and maltodextrins and particularly those maltodextrinscomprising an average number of up to 20, preferably from 2 to 10,particularly preferably 4 to 7 glycosidic units. In many embodiments ofthe present invention, the poly(saccharides) comprise pyranose and/orfuranose units.

The builder/activators according to the present invention are obtainedby a process which comprises oxidative cleavage of a poly(saccharide)comprising a vicinal diol moiety with an oxidising agent for vicinaldiols to introduce carboxylic acid functionality. A wide range ofoxidising agents for vicinal diols can be employed, including halogensystems such as hypochlorite, or periodate and chlorite or peroxygensystems. When the poly(saccharide) is a poly(glycoside), it will berecognised that a glycosidic moiety comprises a number of functionalgroups which can be oxidised by the oxidising agent, notably the C2/C3vicinal diol, and the C6 primary alcohol. Oxidants recognised in the artas selective oxidants for the C6 position of poly(glycosides), such asnitric acid- or N₂ O₄ -based systems are not suitable for use asoxidising agents in the present invention. An oxidising system can beemployed in the present invention which, although an oxidant for theC2/C3 vicinal diol of a poly(glycoside), is not selective for oxidativecleavage at this position. An example of such a non-selective oxidisingsystem is hypochlorite at a pH of about 4 or less, with which oxidationof the C6 position may also occur. In many embodiments, however, it ispreferred that the oxidising system employed is one suitable forselective or preferential oxidative cleavage at the C2/C3 position of apoly(glycoside). Examples of oxidising systems that are suitable foroxidative cleavage selectively or preferentially at the C2/C3 positionof a poly(glycoside) include hypochlorite at alkaline pH; periodateoxidation followed by a chlorite oxidation; and lead tetraacetate.Particularly when the poly(saccharide) comprises a poly(glycoside)comprising an average number of from 2 to 10 glycosidic units, oneoxidising system that can be employed comprises hydrogen peroxide in thepresence of an oxytungsten catalyst.

The oxidation step is usually carried out in aqueous dispersion,insoluble poly(saccharides) being in suspension, whereas solublepoly(saccharides) are in solution. The oxidation is usually carried outat ambient temperature, or only slightly above ambient temperature, forexample from about 15° C. to about 35° C., preferably from about 20° C.to about 30° C., although it will be recognised that higher temperaturescould be employed if desired. When an alkaline hypochlorite or peroxygenoxidant (i.e. a selective C2/C3 oxidant) is employed, the mole ratio ofoxidant to poly(saccharide) (calculated as glycoside by dividing themass of poly(saccharide) by the molecular weight of a glycoside moiety,162) is often selected to be in the range of from 2:1 to 6:1. It will berecognised that the stoichiometric ratio of a 2 electron oxidantrequired to oxidise a diol to a dicarboxylic acid is 4:1. It istherefore preferred in some embodiments that the mole ratio, with theoxidant calculated as a 2 electron oxidant, is at least 4:1, and isoften less than 5:1, with good results having been achieved with a moleratio of 4.5:1. The oxidation step can also be carried out to goodeffect with a sub-stoichiometric amount of oxidant, for example in themole ratio range of from 2.5:1 to 4:1. By employing a lower mole ratio,it is possible to promote the activator properties of the final productrelative to the builder properties.

The weight ratio of oxidant (in the case of oxidant solutions, theweight of active oxidant in the solution) to poly(saccharide) is oftenselected to be in the range of from 1:1 to 5:1, with ratios in the rangeof from 1.5:1 to 3:1 being preferred in some embodiments. In anoverlapping number of embodiments, it is preferable to employ a weightratio of oxidant:poly(saccharide) at the lower end of the range, andparticularly from 1:1 to 2:1. By selecting a comparatively high ratio ofoxidant to polysaccharide within the broadest range above, the builderproperties in the resultant combined builder/activator are encouraged,whereas by selecting a comparatively low ratio of oxidant topolysaccharide within the broadest range above, the activator propertiesin the resultant combined builder/activator are encouraged.

When the oxidation step is carried out in water, the weight ratio ofwater to poly(saccharide), including any water added with the oxidationsystem, employed in the present invention is often greater than 5:1, andmore often greater than 10:1, and is often less than 30:1, and moreoften less than 20:1. It is advantageous when employing sodiumhypochlorite to select a lower compared with a higher water content inthe oxidation step, such as from 5:1 to 15:1 in that it promotes thecapability of the oxidised product to function as a builder, at aselected ratio of oxidant to poly(saccharide).

The oxidant solution is preferably added to a dispersion of thepoly(saccharide) and other reagents, if any, over a period of time,either incrementally or continuously. Typically, the addition period isin the range of from about 10 minutes to about 5 hours, with additionperiods in the smaller scale preparation often taking at least 30minutes and in many instances from 1 hour to 3 hours, and particularlyfrom 1.5 hours to 2.5 hours. On a larger scale, the addition period istypically controlled by the rate at which the oxidant can be transferredinto the reaction vessel and will often take from about 10 to 60minutes.

On completion of the oxidant addition, the reaction mixture is usuallystirred for a time to allow the desired amount of oxidation to takeplace. Reaction times are generally in the range of from several hours,such as 6 to 12 hours, to 24 hours or longer.

On completion of the desired reaction time, the oxidised polysaccharideis separated from the reaction medium. The oxidised poly(saccharide) isusually water soluble, but is generally not soluble in the presence ofhigh concentrations of organic solvent. The oxidised poly(saccharide) istherefore commonly extracted from the reaction medium by the addition ofa volatile, water miscible organic solvent such as ethanol or acetone,in an amount so as to cause the poly(saccharide) to form a precipitate.The precipitate can then be extracted by conventional means, mostcommonly by filtration, and can then be washed by the use of a volatilewater-miscible organic solvent to remove water remaining in the product,with commonly the same solvent as used to effect the precipitation beingemployed. When the oxidation step precedes the acetylation step, theoxidised poly(saccharide) can be employed in the acetylation stepwithout intermediate drying, but usually, the oxidised poly(saccharide)is dried. Commonly air drying is employed, often at elevatedtemperature, such as up to 100° C., with reduced pressure being employedif desired.

In addition to the oxidation step, the process by which thebuilder/activators according to the present invention are obtainablealso comprises an acylation step. For the purposes of the description ofthe acylation step, the expression poly(saccharide) includes the productof an oxidation step according to the present invention. For theacylation step to be effective, the poly(saccharides) must comprise anacylatable moiety, commonly a hydroxyl group. It will therefore berecognised that the oxidation step, where this precedes the acylationstep, is controlled in such a way as to ensure that an acylatable moietyor moieties remain in the poly(saccharide) after the oxidation iscompleted. This is of particular importance for poly(saccharides) inwhich only vicinal diol moieties are present. The purpose of theacylation step is to acylate at least a portion of the acylatablemoieties in the poly(saccharide). The acylation step can employ a widerange of acylating agents depending, for example, on the acyl group itis desired to introduce onto the poly(saccharide). The nature of theacyl group will be determined by the nature of the peracid it is desiredto produce when the builder/activator is employed in a detergentcomposition. For example, if it were desired to produce peracetic acidfrom the detergent composition, an acetylating agent would be employed,whereas to produce pernonanoic acid, a nonanoylating agent would beemployed. The acylating agent will often be selected from acidanhydrides and acid halides, particularly chlorides, with the use ofacid anhydrides generally being preferred, although cost andavailability may favour the use of the acid chloride in certain cases.Examples of peracids which it would be desirable to produce from thebuilders according to the present invention include aromatic, aliphaticand cycloaliphatic peracids, often those comprising up to 10 carbonatoms. Examples of aromatic peracids include particularly perbenzoicacid and substituted, especially para potassium sulpho substituted,perbenzoic acids. Examples of aliphatic peracids include up to C9aliphatic peracids, particularly peracetic acid and pernonanoic acid,with the acylating agents being chosen accordingly. Particularlypreferred acylating agents are acetic anhydride and nonanoyl chloride.

The conditions employed in the acylation step largely depend on thenature of the acylating agent being employed. When an anhydride is beingemployed, the acylation is carried out in the presence of an organicsolvent, and in the substantial absence of water. The organic solvent isselected on the basis of compatibility with the anhydride employed toavoid waste in side reactions with the solvent, and on the ability to atleast partially solubilise the poly(saccharide). Organic solventsinclude chlorinated solvents such as dichloromethane and tertiary aminessuch as triethylamine. A preferred solvent, particularly when aceticanhydride is employed as acylating agent, is acetic acid.

When an anhydride is being employed as acylating agent, acylation can becarried out a temperature ranging from ambient temperature, such asabout 20° C. to reflux temperature. Acylation catalysts, such as HClO₄may be employed if desired. The weight ratio of anhydride topoly(saccharide) is often in the range of from 1:2 to 5:1, and ispreferably from 1:1 to 3:1.

In some embodiments, it is preferable to employ a high boiling pointinert hydrophobic organic liquid during product recovery, in addition toany of the previously identified organic solvents, for exampleintroduced into the recovery step in an amount of up to about 10 partsby volume per part by weight of the oxidised poly(saccharide) and in anumber of instances from 2.5 to 7.5 parts vol/wt. The inert liquid isimmiscible or only poorly miscible with the reaction mixture and forms asecond phase. A characteristic of the liquid is to have a higher boilingpoint than the reaction mixture, ie the organic solvent and any residualacylating agent employed in step b). In such embodiments, the volumeratio of low boiling solvent to high boiling organic liquid is oftenchosen in the range of from 5:1 to 1:2. The high boiling point inertliquid usually has a boiling point of at least 120° C. and normally upto about 300° C., and in many instances from 150 to 250° C. Suchhydrophobic liquids are often selected from aliphatic and aromatichydrocarbons and particularly mixtures thereof, having the appropriateboiling point such as those obtainable as distillation cuts from crudeoil. Other viable hydrophobic liquids include chlorinated derivatives ofhydrocarbons having high boiling point. A particularly desirablecombination of solvent/liquids comprises a mixture of from 6 to 20volumes of acetic acid per 10 volumes of a hydrocarbon cut having aboiling point of from 150 to 250° C.

Recovery of the product of the acylation step often includesdistillation or evaporation of the low boiling point solvent. Thepresence of the inert hydrophobic liquid during suchevaporation/distillation encourages the formation of a particulate soliddispersed within the inert phase, aiding recovery of material from thereaction vessel dispersed in the inert liquid and readily separabletherefrom by filtration or centrifugation techniques. Additional productcan sometimes also be recovered from separated inert liquid. Whereappropriate after purification steps, the inert liquid can be recycledto a subsequent batch.

When an acid chloride is employed as acylating agent, the reaction canbe carried out under known conditions for the acylation of hydroxygroups. Examples of such processes include those disclosed in U.S. Pat.Nos. 4,536,314; 4,704,236; 4,908,474; and 5,380,917, each of which isincorporated herein by reference. Particularly for poorly water solubleacid chlorides such as nonanoyl chloride, acylation of thepoly(saccharide) is effected first dissolving the acid chloride in awater miscible hydroxyl-free solvent prior to introduction into thereaction vessel. Suitable solvents include water miscible ketones,sulphoxides, amides, nitrides and cyclic ethers. Ketones are preferred,preferably acetone. In certain embodiments of the present invention,good results have been achieved employing a weight ratio of acidchloride to hydroxyl-free organic solvent in the range of from 2:1 to1:2, with a weight ratio of acid chloride to poly(saccharide) of from1:1 to 3:1.

The process according to the present invention can comprise oxidation ofthe poly(saccharide) prior to the acylation step, or, alternatively, thepoly(saccharide) can be acylated prior to the oxidation step. However,when the poly(saccharide) is acylated prior to the oxidation, it isbelieved that the oxidation step can cause the loss of some of the acylgroups from the poly(saccharide), with a consequent reduction inactivator performance. It is therefore usually preferred for theoxidation step to precede the acylation step.

According to a third aspect of the present invention, there are provideddetergent compositions, characterised in that they comprise a peroxygenbleach and a detergent builder/activator obtainable by a processcomprising the independent steps of:

a) oxidising a polysaccharide with an oxidising agent to introducecarboxylic acid functionality, and

b) acylating the polysaccharide with an acylating agent.

The detergent compositions according to the present invention can beeither solid or liquid detergents. The detergent compositions will bedescribed herein with reference to solid compositions, but it will berecognised that liquid compositions will in many respects comprisesimilar components to the solid compositions, but that the relativeamounts of these components will often vary in ways conventional in theliquid detergent art. When a liquid detergent is employed, preferredcompositions are those comprising alkali metal superperborates disclosedin European patent application no. 0 565 017, incorporated herein byreference.

In many preferred solid detergent compositions according to the presentinvention, one or more of the composition components are selected withinthe following ranges (% w/w):

    ______________________________________                                        builder/activator                                                                             1 to 60%, particularly 5 to 40%                                 peroxygen bleach 2 to 40%, particularly 5 to 30%                              surfactant 2 to 40%, particularly 5 to 25%                                    diluent 0 to 70%, particularly 5 to 50%                                       additives 1 to 10% in total.                                                ______________________________________                                    

Peroxygen bleaches that can be included in the detergent compositionsaccording to the present invention include perborate salts, percarbonatesalts, and permono and perdisulphate salts. In many cases, the peroxygenbleaching agent will be selected from sodium percarbonate, sodiumperborate monohydrate and sodium perborate tetrahydrate.

The surfactants for incorporation in solid compositions of the presentinvention can be selected from particulate or flaky anionic, cationic,non-ionic, zwitterionic, amphoteric and ampholytic surfactants and canbe either natural soaps or synthetic. A number of suitable surfactantsare described in chapter 2 of Synthetic Detergents by A Davidsohn and BM Milwidsky (6th edition) published in 1978 by George Godwin Ltd andJohn Wiley & Sons, incorporated herein by reference. Without limiting tothese surfactants, representative sub-classes of anionic surfactants arecarboxylic acid soaps, alkyl aryl sulphonates, olefin sulphonates,linear alkane sulphonates, hydroxy-alkane sulphonates, long chain andOXO alcohol sulphates, sulphated glycerides, sulphated ethers,sulphosuccinates, alkane sulphonates, phosphate esters, sucrose estersand anionic fluorosurfactants; representative classes of cationicsurfactants include quaternary ammonium or quaternary pyridinium saltscontaining at least one hydrophobic alkyl or aralkyl group,representative classes of nonionic surfactants include condensates of along chain alkanol with either polyethylene oxides or with phenols, orcondensates of long chain carboxylic acids or amines or amides withpolyethylene oxide, and related compounds in which the long chain moietyis condensed with an aliphatic polyol such as sorbitol or condensationproducts of ethylene and propylene oxides or fatty acid alkanolamidesand fatty acid amine oxides; representative classes ofamphoteric/zwitterionic surfactants include sulphonium and phosphoniumsurfactants, optionally substituted by an anionic solubilising group.The proportion of surfactant, expressed as a fraction of all thesurfactant present is often from 2/10 to 8/10ths anionic, from 0 to6/10ths nonionic, and from 0 to 3/10ths for the other surfactants.

In addition to the detergent builder/activators according to the presentinvention, the detergent compositions can comprise an additional builderselected from amongst those which are conventional or contemplated inthe art. Examples of such additional builders include specificallyalkali metal phosphates, particularly tripolyphosphate but alsotetrapyrophosphate and hexametaphosphate, especially the sodium salt ofeach, alkali metal, preferably, sodium carbonate, alkali metal,preferably, sodium borates, and siliceous builders including clays likebentonite, zeolites such as X, Y and MAP zeolites (EP-A-0 552 053) andlayered silicates such as the product available under the tradedesignation SKS6. When such an additional builder is employed, it isusually present in the composition at a lower concentration than that atwhich they are conventionally employed in the absence of thebuilder/activators according to the present inventor. Useful detergentcompositions can also include organic chelating builders includenitrilotrisodium triacetate (NTA), EDTA, EDTMP and DTPMP. Such chelatingbuilders can be employed in a relatively small amount as an augmentingbuilder and peroxygen stabiliser, such as of 1 to 10%.

The detergent compositions can also contain diluents, in an amountusually of not more than about 70% w/w. Such diluents include sodium andmagnesium sulphate and are less favoured than previously bymanufacturers of detergent compositions, who in recent years havepromoted concentrated compositions.

Detergent compositions of the present invention can also contain othersubstances selected for dedicated purposes in detergent compositions,which in some instances are referred to collectively as detergentadditives. Among such additives, the following can be mentioned:additional persalt activators, optical brighteners, foam inhibitors,enzymes, fading inhibitors and anti-redeposition agents, colorants, pHregulators. Such additives for incorporation in persalt-containingdetergent compositions have been described in greater detail in Chapter4 and exemplified in Chapter 7 of the aforementioned work by Davidsohnand Milwidsky and are well known to skilled practitioners. Thus, forexample, the additional bleach activator is typically a compound whichgenerates a peroxyacid or an anion thereof by reaction with a peroxygenand is employed in a mole ratio of about 4:1 to 1:2 peroxygen:activatorfor monoactivating activators and proportionately for multiactivatingactivators. The range of activators a1 to a20 described by SolvayInterox Ltd in EP-A 0 565 017 can be employed herein, including TAED,SNOBS, sodium isononoyloxybenzenesulphonate, TAGU or sugar esters.Another type of additional activator for washing/bleaching compositionscomprises certain transition metal salts and/or complexes, for examplecertain manganese, cobalt, and titanium complexes, sometimes employed inconjunction with a calcium promoter, as described in European PatentApplication-A-0 272 030. Commonly used optical brighteners includestilbene derivatives. Common antiredeposition agents includecarboxymethyl cellulose and polyvinyl pyrrolidone.

In a variation on detergent compositions, there are also provided bleachadditive compositions, which comprise peroxygen bleaches and detergentbuilder/activators according to the present invention. Such bleachadditive compositions are often employed to augment the cleaningproperties of non-bleach containing detergent systems, and so aregenerally free from, or contain below 2% w/w, surfactants, althoughother components of detergent compositions may be present. The bleachadditive compositions often comprise up to 75% w/w, preferably up to 55%w/w, peroxygen bleach and up to 75% w/w, preferably up to 55% w/w,builder/activator.

The washing and/or bleaching compositions can be employed for washingand or bleaching operations, such as for domestic laundry in accordancewith currently described operation conditions for respectively persaltor persalt plus activator-containing compositions.

In certain embodiments of the present invention, the detergentbuilder/activators can be present in detergent compositions comprisingan inorganic peroxygen compound at least in part as a coating for theperoxygen compound. The use of such a coated peroxygen compound isbelieved to be particularly desirable when the peroxygen compoundcomprises sodium percarbonate. Such use is believed to offer not onlythe advantages of detergency building and bleach activation, but also toenhance the stability of the peroxygen. When a coated peroxygen compoundis employed, the coating is often up to about 10% by weight, usuallyless than 5% by weight, and often greater than about 2% by weight, ofthe coated peroxygen. The detergent builder/activator according to thepresent invention may be employed either as the sole coating agent, oras one component in a mixture of coating agents.

According to a preferred aspect of the present invention, there isprovided a detergent builder/activator obtainable by a processcomprising:

a) in a first step, oxidatively cleaving a poly(glycoside) at the C2/C3vicinal diol to introduce carboxylic acid functionality with an alkalinesolution of sodium hypochlorite, the mole ratio of hypochlorite topoly(glycoside), calculated as glycoside, being from 2:1 to 6 to 1, and

b) in a second step, acetylating the oxidised poly(glycoside) from a)with acetic anhydride, the weight ratio of acetic anhydride:oxidisedpoly(glycoside) being from 1:1 to 3:1.

Having described the invention in general terms, specific embodimentsthereof are described in greater detail by way of example only.

In the Examples, the following general methods were followed, unlessotherwise specified.

Oxidation Step

10 g of poly(saccharide) was dispersed in 100 g demineralised water atroom temperature (20 to 25° C.). 200 ml of 10% w/v sodium hypochloritesolution was added with stirring to this dispersion over a period of 2hours.

On completion of the addition, the reaction mixture was stirred for 24hours at room temperature. The reaction mixture was then cooled to 5° C.and then poured into 1.5 to 2 times the volume of reaction mixture ofcold (5° C.) methanol. This mixture was then filtered to extract thesolid oxidised poly(saccharide), and the solid washed with coldmethanol. The product is then vacuum dried.

Acetylation Step

12 g of dry poly(saccharide) is added with stirring to a mixture of 20 gacetic anhydride and 110 g acetic acid. The reaction mixture is thenheated to reflux temperature, and held at this temperature for 2 hours.After this period, the reaction mixture is allowed to cool to roomtemperature. The solid obtained is extracted by filtration, washed withethyl acetate and air dried.

Builder Performance

The ability of the oxidised poly(saccharides) to sequester calcium andmagnesium ions was measured by potentiometric titration. A millivoltmeter fitted with a divalent cation selective electrode and calomelreference electrode was calibrated by noting the potential against arange of standard calcium or magnesium ion solutions (10⁻⁵ to 10⁻³ M),in the presence of 0.001M NaOH, and a calibration graph produced. Asample (0.1 g) of the oxidised poly(saccharide) is then dissolved in 100mls 0.001M NaOH solution. Aliquots of 0.1M Mg or Ca solution are thenadded, and the potential noted. For the addition of a given amount of Mgor Ca ions, the concentration of non-sequestered Mg or Ca ions in thesolution can be calculated from the calibration graph, giving bysubtraction the amount of ions sequestered. The results are expressed asa percentage of ions sequestered, and are quoted for the addition of 2 gor 5 g of Mg or Ca per 100 g of oxidised poly(saccharide).

Bleach Activator Performance

The bleach activator performance was measured by dissolving a 3.8 gsample of acylated product in the presence of 22.8 g sodium perboratemonohydrate in demineralised water at 25° C. and pH 9 with agitationprovided by a paddle stirrer. Aliquots of the solution were removed atregular intervals after the addition of the sample and analysed forperacid by iodometric titration in ice/water/glacial acetic acid withsodium thiosulphate solution.

EXAMPLE 1

A sample of unmodified wheat starch commercially available from SigmaChemicals was oxidised by the general method given above, except that 15g of starch was employed, with the other reagent quantities being scaledproportionately, yielding 9.1 g oxidised product. Analysis by ¹³ C NMRshowed peaks at 170 to 180 ppm relative to dioxane which were attributedto carboxyl carbons. The oxidised starch was found to sequester 69% Caat 2 g Ca per 100 g oxidised starch and 50% Ca at 5 g Ca per 100 goxidised starch.

6 g of the oxidised starch was acetylated by the general method givenabove, with other reagent quantities reduced proportionately, yielding2.4 g acetylated product. Analysis of the product by IR showed a peak at1740 cm⁻¹ which was attributed to the presence of acetate groups.Analysis by ¹ H NMR showed peaks at 1.8 to 2.4 ppm relative to TMS whichwere attributed to the presence of acetate groups. Analysis by ¹³ Csolution NMR showed peaks at 165 to 180 ppm relative to dioxane whichwere attributed to the presence of carboxyl groups. ¹³ C solid state NMRrelative to tetramethylsilane showed a peak at 171 ppm which wasattributed to the presence of carboxylic acid groups, and peaks at 21.1ppm and 14.3 ppm which were respectively attributed to the presence ofmethyl moieties of acetate groups.

EXAMPLE 2

A sample of unmodified wheat starch commercially available from SigmaChemicals was oxidised and subsequently acetylated by the generalmethods given above.

Evaluation of the activator performance showed that 16.9 mg/l per 1.5 gsample of peracetic acid had been produced 3 minutes after addition ofthe sample.

EXAMPLE 3

A sample of rice starch commercially available from Sigma Chemicals wasoxidised and subsequently acetylated by the by the general methods givenabove.

Evaluation of the activator performance showed that 12.6 mg/l per 1.5 gsample of peracetic acid had been produced 1 minute after addition ofthe sample.

EXAMPLE 4

A sample of cellulose powder commercially available from AldrichChemicals was oxidised and subsequently acetylated by the by the generalmethods given above.

Evaluation of the activator performance showed that 63.4 mg/l per 1.5 gsample of peracetic acid was present in solution 5 and 10 minutes afteraddition of the sample.

Comparison C5

The builder and bleach activator performances of the wheat starchemployed in Examples 1 and 2 were measured. No calcium sequestration wasobserved, and no peracetic acid was produced.

EXAMPLE 6

A sample of unpurified wheat starch commercially available from SigmaChemicals was oxidised by the general method given above, except that10.19 g of starch was suspended in 177 ml water and 83 mls of sodiumhypochlorite solution (17.9% conc) was introduced, yielding 9.0 goxidised product. The oxidised starch was found to sequester 50% Ca at5.2 g Ca per 100 g oxidised starch.

5.07 g of the oxidised starch was acetylated by the general method givenabove, with other reagent quantities altered proportionately, yielding1.74 g acetylated product. Evaluation of the activator performanceshowed that 8.4 mg/l per 1.5 g sample of peracetic acid was present insolution 5 minutes after addition of the sample.

EXAMPLE 7

The procedure of Example 6 was followed, except that the starch (10.07g) was dispersed in only 20 ml water. The same volume/strength of sodiumhypochlorite solution was used, providing the same ratio of activechlorine to starch as in Example 6, but in the presence of a loweramount of water, during the reaction, yielding 9.2 g oxidised product.The oxidised starch was found to sequester 62% Ca at 5.2 g Ca per 100 goxidised starch. Evaluation of the activator performance showed that10.8 mg/l per 1.5 g sample of peracetic acid was present in solution 5minutes after addition of the sample.

EXAMPLE 8

The procedure of Example 7 was followed, except that only 56 mls of thesame strength sodium hypochlorite solution was used, providing 2/3rdsthe ratio of active chlorine to starch as in Example 7, yielding 9.7 goxidised product. The oxidised starch was found to sequester 33% Ca at5.2 g Ca per 100 g oxidised starch, indicating that even at a very lowratio of oxidant:starch, a product having significant calcium exchangecapability is obtainable when the oxidant solution contains only arelatively small amount of water.

Evaluation of the activator performance showed that 13.6 mg/l per 1.5 gsample of peracetic acid was present in solution 5 minutes afteraddition of the sample.

EXAMPLE 9

In this Example, the process was carried out on approximately a 40×scale. In step 2, oxidised starch (500 g, obtained by a scaled uprepetition of Example 6) was mixed with acetic anhydride (937.5 g) insolution in 4375 g acetic acid, and the mixture stirred at refluxtemperature (120° C.) for 2 hours. A commercial high boiling petroleumcut available under trade mark SHELLSOL AB (5 liters, bp 170° C.) wasintroduced into the reaction mixture, and acetic acid was removed undervacuum, by which time the temperature of the mixture had fallen to 60°C. The mixture was then permitted to cool overnight and the solidsdispersed in the petroleum cut were filtered, washed with ethyl acetate,refiltered and dried under vacuum. 608 g product was recovered.

Evaluation of the activator performance showed that 4.8 mg/l per 1.5 gsample of peracetic acid was present in solution 5 minutes afteraddition of the sample.

What is claimed is:
 1. A detergent builder/activator obtained by aprocess comprising subjecting a poly(saccharide) having at least onevicinal diol moiety and having in addition, at least one acylatablemoiety to the steps of:a) first, oxidative cleavage of the vicinal diolmoiety with an oxidizing agent for vicinal diols to introduce carboxylicacid functionality, the oxidizing agent being in a quantity such thatthe weight ratio of oxidizing agent to poly(saccharide) is from 1:1 to5:1, in order to obtain an oxidized poly(saccharide) comprisingcarboxylic acid groups and still containing at least one acylatablemoiety; and then b) acylation of the acylatable moiety of the oxidizedpoly(saccharide) into an ester group with an acylating agent chosen fromacid anhydrides and acid halides, the weight ratio of acylating agent topoly(saccharide) being from 1:2 to 5:1 in the case of an acid anhydrideand from 1:1 to 3:1 in the case of an acid halide.
 2. A process for theproduction of a detergent builder/activator comprising subjecting apoly(saccharide) having a vicinal diol moiety and having in addition, atleast one acylatable moiety to the steps of:a. first, oxidative cleavageof the vicinal diol moiety with an oxidising agent for vicinal diols tointroduce carboxylic acid functionality, the oxidizing agent being in aquantity such that the weight ratio of oxidizing agent topoly(saccharide) is from 1:1 to 5:1, in order to obtain an oxidizedpoly(saccharide) comprising carboxylic acid groups and still containingat least one acylatable moiety; and then b. acylation of the acylatablemoiety of the oxidized poly(saccharide) into an ester group with anacylating agent chosen from acid anhydrides and acid halides, the weightratio of acylating agent to poly(saccharide) being from 1:2 to 5:1 inthe case of an acid anhydride and from 1:1 to 3:1 in the case of an acidhalide.
 3. A detergent builder/activator according to claim 1, whereinthe poly(saccharide) comprises a poly(glycoside).
 4. A detergentbuilder/activator according to claim 3, wherein the poly(glycoside) isselected from the group consisting of starches and maltodextrins.
 5. Adetergent builder/activator according to claim 1, wherein the acylatingagent comprises acetic anhydride or nonanoyl chloride.
 6. A detergentbuilder/activator according to claim 1, wherein the acylation step isconducted in the presence of acetic acid as solvent for the acylatingagent.
 7. A detergent builder/activator according to claim 1, wherein,after the acylation step, a high boiling point inert hydrophobic liquidis mixed with the reaction mixture containing acylated oxidizedpoly(saccharide), and lower boiling solvent is then evaporated ordistilled from the mixture, thereby producing a dispersion of acylatedoxidized poly(saccharide) in the hydrophobic liquid.
 8. A detergentbuilder/activator according to claim 1, wherein the poly(saccharide)comprises a poly(glycoside) and wherein the oxidizing agent is selectedfrom alkaline sodium hypochlorite and hydrogen peroxide.
 9. A detergentbuilder/activator according to claim 8, wherein the mole ratio of sodiumhypochlorite or hydrogen peroxide to poly(saccharide), calculated asglycoside, is from 2:1 to 6:1.
 10. A detergent builder/activatoraccordingly to claim 1, wherein the oxidizing agent comprises alkalinesodium hypochlorite, and wherein the weight ratio of sodium hypochloriteto poly(saccharide), calculated as glycoside, is from 1:1 to 2:1.
 11. Adetergent builder/activator according to claim 3, wherein the weightratio of water:poly(glycoside) in step a) is in the range of from 5:1 to15:1.
 12. A detergent builder/activator according to claim 3, whereinthe oxidizing agent is introduced into a suspension of poly(glycoside)in water of from 1:1 to 1:3 parts wt:volume.
 13. A detergent or bleachactivator composition, comprising a peroxygen bleach and a detergentbuilder/activator obtainable by a process comprising the independentsteps of:a) oxidising a polysaccharide with an oxidising agent tointroduce carboxylic acid functionality, and b) acylating thepolysaccharide with an acylating agent.
 14. A detergentbuilder/activator obtained by a process comprising:a) in a first step,oxidatively cleaving a poly(glycoside) at the C2/C3 vicinal diol tointroduce carboxylic acid functionality with an alkaline solution ofsodium hypochlorite, the mole ratio of hypochlorite to poly(glycoside),calculated as glycoside, being from 2:1 to 6:1, and b) in a second step,acetylating the oxidised poly(glycoside) from step a) with aceticanhydride, the weight ratio of acetic anhydride:oxidised poly(glycoside)being from 1:1 to 3:1.
 15. A process for the production of a detergentbuilder/activator comprisinga) in a first step, subjecting apoly(glycoside), to oxidative cleavage at the C2/C3 vicinal diol tointroduce carboxylic acid functionality with an alkaline solution ofsodium hypochlorite, the mole ratio of hypochlorite to poly(glycoside),calculated as glycoside, being from 2:1 to 6:1, and b) in a second step,acetylating the oxidised poly(glycoside) from step a) with aceticanhydride, the weight ratio of acetic anhydride:oxidised poly(glycoside)being from 1:1 to 3:1.
 16. A detergent or bleach activator compositioncharacterised in that it comprises a detergent builder/activatoraccording to any one of claims 1, 3, 4, 5, 6, 12, 14, or
 17. 17. Adetergent builder/activator according to claim 1 wherein said acylatablemoiety comprises a hydroxyl group.
 18. A process according to claim 2,wherein the poly(saccharide) comprises a poly(glycoside).
 19. A processaccording to claim 18, wherein the poly(glycoside) is selected from thegroup consisting of starches and maltodextrins.
 20. A process accordingto claim 2, wherein the acylating agent comprises acetic anhydride ornonanoyl chloride.
 21. A process according to claim 2, wherein theacylation step is conducted in the presence of acetic acid as solventfor the acylating agent.
 22. A process according to claim 2, wherein,after the acylation step, high boiling point inert hydrophobic liquid ismixed with the reaction mixture containing acylated oxidizedpoly(saccharide), and lower boiling solvent is then evaporated ordistilled from the mixture, thereby producing a dispersion of acylatedoxidized poly(saccharide) in the hydrophobic liquid.
 23. A processaccording to claim 2, wherein the poly(saccharide) comprises apoly(glycoside) and wherein the oxidizing agent is selected fromalkaline sodium hypochlorite and hydrogen peroxide.
 24. A processaccording to claim 23, wherein the mole ratio of sodium hypochlorite orhydrogen peroxide to poly(saccharide), calculated as glycoside, is from2:1 to 6:1.
 25. A process accordingly to claim 2, wherein the oxidizingagent comprises alkaline sodium hypochlorite, and wherein the weightratio of sodium hypochlorite to poly(saccharide), calculated asglycoside, is from 1:1 to 2:1.
 26. A process according to claim 18,wherein the weight ratio of water:poly(glycoside) in step a) is in therange of from 5:1 to 15:1.
 27. A process according to claim 18, whereinthe oxidizing agent is introduced into a suspension of poly(glycoside)in water of from 1:1 to 1:3 parts wt:volume.
 28. A process according toclaim 2 wherein said acylatable moiety comprises a hydroxyl group.